Depth adjustment for motor-driven cutting tools



Oct. 14, 1952 i E. P. SACREY 2,613,704.

DEPTH ADJUSTMENT FOR MOTOR-DRIVEN CUTTING TOOLS Filed March 11, 1950 Patented Oct. 14, 1952 DEPTH ADJUSTMENT FOR MOTOR-DRIVEN CUTTING TOOLS Elmer P. Sacrey, Syracuse, N. Y.

Application March 11, 1950, Serial No. 149,193

This invention relates to motor driven tools and particularly to wood working tools, as routers, and to means for adjusting the depth of the cut by the tool.

It has for its object a depth gauge which is particularly simple and accurate and easily operable, and consists of a ring rotatably mounted on the body of the tool around the upper end of the passage in which the motor casing is adjustable axially, the ring having calibrations for different depths and operable initially with its zero calibration in line with the calibration on the motor casing when the tool is set in starting or zero position, and the motor casing is rotatable to carry its calibration in line with the predetermined depth calibration of the ring.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all theviews.

Figure 1 is an elevation, partly in section, of a router embodying this invention.

Figure 2 is a sectional view, partly broken away, on line 2-2, Figure 1.

Figure 3 is an enlarged fragmentary cross sectional view on line 3-3, Figure 2.

Figure 4 is an enlarged sectional view on line 4-4, Figure l.

The router is of the general type shown in Patent No. 1,899,883, February 28, 1933.

I designates the body of the router, this comprising an upper tubular or sleeve portion 2 enclosing a cylindrical passage and a base portion having a fiat bottom plate 3 which engages the surface of the work in which a recess is to be cut out or routed, and limits the depth of the cut. The body is formed with diametrically opposing handles 4 for holding the tool and pressing it into the work. The body is also formed with slots 5 on diametrically opposite sides below the tubular portion 2, and the tubular portion 2 is split longitudinally at 6 so that the tubular portion is a split sleeve capable of being expanded and contracted. It is held contracted by means as a clamping screw 1 coacting with lugs 8, 9, on opposite sides of the slit 6.

l0 designates the electric motor, this having a cylindrical metal casing H which slidably fits into the passage of the tubular portion 2 of the body when the tubular portion is expanded by loosening the screw 1. The casing is connected to the tubular portion by interlocking spiral 3 Claims. (Cl. 144136) means, as ribs [2, on the casing coacting with complemental grooves l3 on the inner face of the tubular portion 2 so that upon turning of the motor and its casing, the motor is shifted axially to adjust the depth of the out. A tool, as a routing tool i 4 is suitably carried by the shaft of the motor.

The subject matter of this invention-is the means for adjusting the axial position of the motor and the cutter to cut predetermined depths. This means consists of a ring l5 encircling the upper or outer end of the tubular portion 2 and rotatably mounted thereon, the ring having micrometric calibrations It for coacting with a single calibration H on the motor casing II. The ring is frictionally'held in any adjusted position and. as shown the friction means comprises brake shoes l8 located in grooves l9 and 20 on confronting faces of the ring and the tubular portion 2, the grooves extending circumferentially and usually being complete circles. The brake shoes l8 are arcuate, resilient, and of a different arcuate curvature from the grooves so that they are spring loaded when flexed and serve to hold the ring from axial displacement, and also to frictionally hold it from turning movement.

To adjust the depth of the cut, the clamping screw 1 is first loosened and the motor turned along the spiral ways [3 until the end of the cutter is level with the plate 3, that is, in starting position, or level with the face of a spacer between the face 3 and the surface of the work. In other words, the motor is set so that the end of the cutter touches the work. The ring [5 is then turned until its zero calibration is alined with the calibration H on the motor casing. The motor casing is then turned until the calibration I? is alined with a selected depth calibration of the ring. The clamping screw I is then tightened. The router is then operated on the work to cut a recess and push into the recess until the face plate 3, or a spacing device, engages the surface of the work.

By this adjusting ring, a fine micrometer adjustment of the cutter is quickly, easily and accurately made.

What I claim is:

1. In a motor driven tool, a body formed with a cylindrical passage open at one end, a motor having its shaft provided with means for holding a tool and also having a cylindrical casing extending through the open end of the body and slidably fitting the walls of the passage, slidably coacting spiral means connecting the motor casing and the walls of the passage so that upon turning of the casing in the passage, the motor is shifted axially, and a depth gauge comprising a ring provided with depth calibrations, the ring being mounted on the open end of the body and having a rotating movement, friction means between the ring and the body for braking the rotation of the ring, the casing havin -a single calibration, the ring being rotatable relatively to the body and the casing when the casing is turned to position the cutter in zero position, and the casing being also rotatable along the spiral means from zero position to aline its calibration with a selected depth calibrationof the ring, the rin and the body being formed with inner and outer confronting faces formed with circumferentially extending ,grooves and bow spring members in the grooves of a different arouate curvature from that of the confronting faces to frictionally hold the ring from turning.

.2. In a motor driven tool, a body formed with a cylindrical passage, the portion of the body formed with the passagebeing split longitudinally to form a clamp, and means for contacting the body, .a motor having a shaft provided with means for holding a cutting tool, and also having a cylindrical casing slidably fitting the walls of the passage when the cylindrical portion is unclamped, slidably interlocking spiral means connecting the motor casing and the walls of the passage,- whereby upon turning of the motor and the casing, the motor casing and tool are shifted endwise in the passage, and a depth gauge com prising a ring provided with depth calibrations,

thering being mounted on the open end of the body and having arotating movement, friction means between the ring and the body for braking the rotation of the rin the casing having a single calibration, the ring being rotatable relatively to the'body and the casin when the casing is turned to position the cutter in zero posi-- ,tion, and the casing being also rotatable along the spiral means from zero position to aline its calibration with a selected depth calibration of the ring.

3. In a motor driven tool, a motor having its shaft provided with means for holding a tool and also having a cylindrical casing extending therefrom and coaxial with said shaft, a body having at one end a bottom plate perpendicularly related to said shaft and adapted to engage a surface of the work piece, said body having a cylindrical passage therethrough opening at the other end thereof remote from said bottom plate and coaxial with said cylindrical casing and slidably receiving the same, cooperating interengaging spiral means on the passage walls of said body and the outer surface of said cylindrical casing, operative upon relative rotation between the casing and the body to effect relative axial move- :ment, accalibrated ring mounted on said body at said other end thereof, a longitudinal index marking on said casing, said ring being rotatable on said body to align the zero calibration with the index marking to indicate the initial posi tion with the tool invcontact with the working surface, and vsaid motor casing being rotatable in said body and axially movable therein to a final position wherein a selectedcalibration of the ring is aligned with the index marking indicating the desired .depthof cut to be obtained.

ELMERP. SACREY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

